Surprise, surprise. Bob Villa [This Old House] has a video for us that shows, in great detail, how to develop a better sounding recording space.

I always think of my house when I think of Bob villa, so, the surprise may be all mine.

Some before and after recording audio clips that give a really fair difference in what kind of sound exists and how it will be modified, acoustically, with a fairly simple procedure.

This video uses absorbent panels placed at right angles from the source of sound. One in front, one directly behind and an insulation filled acoustically transparent panel on the left and right hand sides respectively.

While this may not be the way I would construct the sound containment area, it is highly effective, and isn't built wrong at all, just different from me and maybe even you.

The only thing I might change would be the full width and length cloth. I would install this covering in smaller sheets.

Other than that, look at it and fit it into your plans if at all possible.